'99 test run spectrometer analysis

 
 
We have used the hadron spectrometer to detect the recoil proton during our photon and electron runs.
 

Characteristics and settings

      We used the hadron arm at two different kinematics:
      • central momentum 2.037 GeV/c and 1.867 GeV/c at 34.86o and 36.49o respectively
      • the corresponding dipole fields were measured to be 7517.7 Gauss and 6890.3 Gauss respectively.


      A few differences with a regular setting have to be mentionned:

      • the offset measurement device were unavailable during the commissioning period, which means an uncertainty on the position of the focal plane of the spectrometer. The offsets were set to be zero in the header file we used with espace
      • we could not use the BPM to rephase our raster: we chose to ignore the raster in the header file. It's not very important since the raster was small and we don't need to have a good accuracy on the vertex position reconstruction.

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    Hadron data and dedicated cuts
     
      I've tried to get a set of cuts that everyone could use to analyse the photon arm. Those cuts are totally independent except for the coincidence time since only coincidence events were written in our Ntuple. I've chosen to give two sets of cuts. One "loose" cut called cut #1 and one tighter cut called cut #2. The second one is smarter, especially for the production data (last run block).

     
    Run block
    Cut #1
    Cut #2
    1   (runs 1429-32)
    		 hrstype=7
    465<tcoinc<540
    -0.02<ph<0.01
    -0.02<th<0.02    		 hrstype=7
    465<tcoinc<540
    -0.015<ph<0.01
    -0.02<th<0.02
    -(A/3) < ph-(B/15)*p < -(C/3)
    with A=1.800, B=0.0044, C=1.768
    2   (runs 1433-36)
    		 hrstype=7
    465<tcoinc<540
    -0.02<ph<0.01
    -0.02<th<0.02    		 hrstype=7
    465<tcoinc<540
    -0.015<ph<0.01
    -0.02<th<0.02
    -(A/3) < ph-(B/15)*p < -(C/3)
    with A=1.800, B=0.0044, C=1.768
    3   (runs 1437-40)
    		 hrstype=7
    465<tcoinc<540
    -0.02<ph<0.01
    -0.02<th<0.02    		 hrstype=7
    465<tcoinc<540
    -0.013<ph<0.008
    -0.02<th<0.02
    -(A/3) < ph-(B/15)*p < -(C/3)
    with A=1.800, B=0.0044, C=1.768
    4   (runs 1441-46)
    		 hrstype=7
    460<tcoinc<560
    -0.03<ph<0.03
    -0.06<th<0.06    		 hrstype=7
    460<tcoinc<560
    1775<p<1945
    -0.06<th<0.06
    -(A/3) < ph-(B/15)*p < -(C/3)
    with A=0.990, B=0.0026, C=0.956